The coordinated multipoint transmission and reception (CoMP) concept is an emerging technology in communication networks. However, in emerging technologies, there are always also some problems that have to be dealt with.
A base station (node B) in a network cell needs to get channel state information from user equipment (UE) in the respective cell. In the coordinated multipoint transmission and reception (CoMP) concept, sound reference signals (SRS) are used in order to obtain these channel state information. Getting channel state information from interfering cells, i.e. overlapping cells, by using sound reference signals (SRS) in uplink (UL), however, will increase the load on the SRS resources as the resource has to be reserved in the interfering cell as well.
In certain cases, SRS is transmitted in the interfering cell only for the base station to be able to estimate antenna correlation. For such purpose, there is no need to send sounding very often. However, for the own cell, there could be a need for more often sounding transmissions to support UL channel aware packet scheduling or short term beam forming in time division duplex (TDD).
Thus, there arises the problem of increased overhead with CoMP sounding.